I wonder about the legal position of recipients of these cheatsheet. In particular, how much trouble can they get into for using the passwords?

Say probate is taking a long time, so someone logs into the bank account and withdraws money for everyday essentials. That’s probably one reason the deceased person left the cheatsheet. But what happens when a bank notices money being withdrawn from the bank account of a dead person? Presumably it gets flagged as fraud. And if the estate is still going through probate, the person withdrawing money might not have a legal right to do that.